Embodiments of the invention relate generally to semiconductor device packages or electronics packages and, more particularly, to an electronics package that includes a conductive cap or shield formed on an insulating structure that surrounds an electrical component provided within the package. A miniaturized package topology is achieved by utilizing the sloped side walls of the insulating structure as a mounting structure for the conductive cap or shield.
State of the art electronics packaging covers a wide range of methods, structures, and approaches from wire bond modules to flip chip modules and to embedded chip modules. Wire bonded modules are a mature packaging approach that is low cost but has limited electrical performance. These modules use wires bonded to chip pads to connect the top I/O pads of power devices to an interconnect structure such as a metal-insulator-metal substrate such as ceramic, Aluminum Nitride (AlN), or Silicon Carbide (SiC) substrate with patterned metal on top and bottom. Wire bonds have inherently high inductance, generally high series resistance, current crowning on the bond pads, and microcracking within the semiconductor devices near bonding sites. An exemplary construction of a prior art wire bond electronics package 10 is illustrated in FIG. 1 with two power semiconductor devices 12 mounted onto a leadframe 14 using component attach material 16. Portions of the leadframe 14 extend beyond the molding resin 26 forming terminals 18. Wire bonds 20 connect die pads 22 located on the active surface 24 of semiconductor devices 12 to selected areas on the leadframe 14. Molding resin 26 encapsulates semiconductor devices 12, wire bonds 20, and exposed portions of leadframe 14. PowerRibbon© Bonding (K&S) is a modified version of power module wire bonding that replaces Al wire bonds with Al ribbons that use thermos-compression to bond to the chip pads. Beneficially, PowerRibbon© Bonding has lower resistance and therefore is targeted for higher current modules. However, PowerRibbon© Bonding has high inductance and can cause substrate microcracking.
Prior art flip chip modules experience reduced semiconductor substrate damage as compared to wire bond packages through the use of solder bumps, which have larger current carrying cross-sections than wire bonds. A general construction of a prior art flip chip electronic package 28 is illustrated in FIG. 2 with two semiconductor devices 12 attached to a top side metal layer 30 of substrate 32 by means of flip chip solder bumps 34. Thermal cooling is achieved with thermal connections 36 formed on the back side 38 of semiconductor devices 12. Molding resin 26 encapsulates the semiconductor devices 12, with portions of the top side metal layer 30 extending beyond the molding resin 26 forming terminals 18. While flip chip modules such as that illustrated in FIG. 2 provide some advantages over wire bond technology, the flip chip solder bumps have poor electrical conductivity, are susceptible to solder fatigue, are susceptible to electro-migration and provide a very poor thermal cooling pathway.
Prior art embedded device modules, such as the embedded device module 40 illustrated in FIG. 3 fabricated using General Electric Company's power overlay (POL) technology, address many of the limitations of wire bond and flip chip packages by eliminating wire bonds and solder bumps and replacing them with direct metallization contacts. In the embedded device module 40, semiconductor devices 12 are mounted onto a dielectric film 42. A post connector 44 is also attached to the dielectric film 42 to provide a top-to-bottom electrical connection for the module 40. Microvias 46 are formed through the dielectric film 42 to the input/output (I/O) contact pads 22 of semiconductor devices 12 and to the post connector 44. A metallization layer 48 is applied to the outer surface of the dielectric film 42, the microvias 46 and the exposed pads 22 to form an electrical connection to the semiconductor devices 12. The dielectric film 42 with attached semiconductor devices 12 and post connector 44 is bonded to a power substrate 32 using an electrically conductive component attach material 50 such as solder. The gaps between semiconductor devices 12 and post connector 44 are filled with a molding resin 26. The embedded device module 40 has reduced parasitics (e.g., resistance, capacitance, and inductance) and a superior thermal performance as compared to wire bond modules or flip chip modules.
Despite the advantages of an embedded device module construction, POL technology is more complex, less mature, and higher cost than wire bond and flip chip approaches. Electrical connections within the module 40 are typically formed by either forming through holes in module 40 using laser drilling and hole metallization or by forming a via to an inserted I/O structure or frame adjacent to the device that provide vertical connections. These approaches increase the complexity and cost of the module and can increase the module footprint.
In any of the above-described prior art packaging topologies, it may be desired to shield a semiconductor device or module that is susceptible to electromagnetic emissions or electromagnetic interference (“EMI”) from neighboring integrated circuit elements. Such EMI shielding may be accomplished through the use of an electrically conductive casing or housing that encloses and surrounds the exterior of the electrical package. While prior art EMI shielding housings or casings can be effective to reduce EMI, these structures also have a number of disadvantages, including increasing manufacturing complexity by incorporating additional steps in the form of adhering the housing or casing to the near-completed package structure and fabricating the electrical connections for grounding the housing or casing. These EMI housings or casings also increase package volume and pose a significant limitation to further miniaturization while maintaining or increasing performance.
Accordingly, it would be desirable to provide a new electronics packaging technology that permits construction of a highly miniaturized electronics package that includes shielding for the embedded electrical component. It would further be desirable that such new technology be capable of use for thermal management and grounding for the electronics package.